A dual-pump control system for hydraulic elevators

Abstract

This application discloses a dual-pump control system for a hydraulic elevator, including a hydraulic oil tank, a first hydraulic oil pump, a second hydraulic oil pump, and at least one hydraulic cylinder for driving the elevator up and down. The first and second hydraulic oil pumps supply oil to the hydraulic cylinder. It also includes a first check valve, an upward directional valve, and a downward directional valve. The first check valve is disposed in the oil supply circuit of the hydraulic cylinder. The upward directional valve is connected in parallel to the front end of the first check valve, and the downward directional valve is connected in parallel to the rear end of the first check valve. Both the upward and downward directional valves are connected to the hydraulic oil tank. The advantage of this application is that it uses a dual-pump system to control the hydraulic elevator, reducing the failure rate of elevator shutdowns due to hydraulic pump failure.

Description

Technical Field

[0001] This application relates to the field of elevator control technology, and in particular to a dual-pump control system for a hydraulic elevator. Background Technology

[0002] Hydraulic elevators, as a type of electromechanical special equipment, have advantages over traction elevators, including smooth operation, low noise, and large load capacity. In addition, they are not afraid of heights but not heavy loads and occupy less shaft space. Hydraulic elevators are widely used in low-density buildings such as villas and factories, and have important and broad application prospects.

[0003] To ensure the safe operation of hydraulic elevators, a series of protective measures are implemented, such as overspeed protection valves for downward movement, safety clamps, pipeline pressure detection relief valves, emergency rescue manual pumps, and manual emergency descent valves. However, these safety protection components are all installed on the hydraulic circuit, focusing primarily on rescue operations and minimizing injuries in the event of entrapment or equipment failure. Research and attention have been lacking regarding the protection and monitoring of the hydraulic pump—the heart of the entire hydraulic elevator. If the hydraulic pump malfunctions, the elevator will lack sufficient hydraulic oil to lift the hydraulic cylinders and stop operating. Summary of the Invention

[0004] This application provides a dual-pump control system for hydraulic elevators, which has the advantage of using a dual-pump system to control the hydraulic elevator, thereby reducing the failure rate of elevator stoppage due to hydraulic pump failure.

[0005] The above-mentioned objective of this application is achieved through the following technical solution: a hydraulic elevator dual-pump control system, characterized in that it includes a hydraulic oil tank, a first hydraulic oil pump, a second hydraulic oil pump, and at least one hydraulic cylinder for driving the elevator to lift and lower, wherein the first hydraulic oil pump and the second hydraulic oil pump are used to supply oil to the hydraulic cylinder.

[0006] It also includes a first check valve, an upward directional valve, and a downward directional valve. The first check valve is installed in the oil supply circuit of the hydraulic cylinder. The upward directional valve is connected in parallel to the front end of the first check valve, and the downward directional valve is connected in parallel to the rear end of the first check valve. Both the upward directional valve and the downward directional valve are connected to the hydraulic oil tank.

[0007] This application further specifies that the hydraulic cylinder's oil supply circuit is also equipped with a flow feedback device, a shut-off valve, and a rupture valve.

[0008] This application further provides that the output ends of the first hydraulic oil pump and the second hydraulic oil pump are respectively provided with a first reversing valve and a second reversing valve to control whether the oil circuit is open or closed, and the output ends of the first hydraulic oil pump and the second hydraulic oil pump are also respectively provided with a first relief valve and a second relief valve.

[0009] This application is further configured to include a manual pump and a second check valve, wherein the manual pump is used to supply oil to the hydraulic cylinder, and the second check valve is disposed at the output end of the manual pump, and the output end of the second check valve is connected to the rear end of the first check valve;

[0010] The manual pump is equipped with a third overflow valve at its output end.

[0011] This application is further configured to include a manual emergency descent valve, which is connected in parallel with the downward directional valve.

[0012] This application is further configured to include a control motherboard, which receives the output signal of the flow feedback device, and the control motherboard is used to control the first hydraulic oil pump, the second hydraulic oil pump, the first reversing valve, the second reversing valve, the upward directional valve, and the downward directional valve.

[0013] This application further specifies that the power supply circuit of the first hydraulic oil pump is connected in series with the normally open contact of the first relay KM1 and the first thermal relay FR1;

[0014] The power supply circuit of the second hydraulic oil pump is connected in series with the normally open contact of the second relay KM2 and the second thermal relay FR2;

[0015] It also includes a control loop, which comprises a first branch, a second branch, and a third branch;

[0016] The first branch includes a normally closed contact of a rotary switch, a stop button SB1, a start button SB2, a first relay KM1, and a first thermal relay FR1 connected in series. The start button SB2 is connected in parallel with the normally open contact of the first relay KM1.

[0017] The second branch includes the first contact of a rotary switch connected in series, the normally closed contact of the first relay KM1, the normally open contact of the first thermal relay FR1, the second relay KM2, and the normally closed contact of the second thermal relay FR2.

[0018] The third branch includes the second contact of the rotary switch, the stop button SB4, the start button SB5, the second relay KM2, and the normally closed contact of the second thermal relay FR2. The start button SB5 and the normally open contact of the second relay KM2 are connected in parallel.

[0019] This application further specifies that the control circuit includes an intermediate relay KA2 connected in series and a normally open contact of the intermediate relay KA2. A pressure switching switch is connected in parallel across the two ends of the normally open contact of the intermediate relay KA2. The normally open contact of the intermediate relay KA2 is connected in parallel across the two ends of the normally closed contact of the first relay KM1 and the normally open contact of the first thermal relay FR1.

[0020] The pressure switching switch is controlled by the main control board or by an electrical contact pressure gauge installed in the hydraulic cylinder oil supply circuit.

[0021] This application further specifies that the control circuit also includes a circuit breaker QF2, a fuse FU2, and an emergency stop switch.

[0022] This application further specifies that the power supply circuits of the first hydraulic oil pump and the second hydraulic oil pump are equipped with a circuit breaker QS1 and a fuse FU1.

[0023] In summary, the beneficial effects of this application are as follows:

[0024] 1. This application uses a dual-pump system to control the hydraulic elevator. When one pump fails, the backup pump is started, or when the oil pressure drops, the backup pump is started, thereby reducing the failure rate of the elevator stopping due to hydraulic pump failure.

[0025] 2. The control circuit in this application can automatically start the second hydraulic pump when the first hydraulic pump fails, or automatically start the second hydraulic pump when the oil pressure drops, without the need for manual start-up, and has a certain degree of automation and intelligence;

[0026] 3. The control circuit in this application can be switched to a third branch via a rotary switch and the second hydraulic pump can be controlled via the third branch, thereby allowing maintenance of the first hydraulic pump without affecting the operation of the elevator. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the hydraulic system of the dual-pump control system in this application;

[0028] Figure 2 This is the electrical schematic diagram of the control circuit of the dual-pump control system in this application;

[0029] Figure 3 This is a schematic diagram of the first part of the control loop in this application;

[0030] Figure 4 This is a schematic diagram of the second part of the control loop in this application.

[0031] In the diagram, 1. Hydraulic oil tank; 2. Filter; 3. First hydraulic oil pump; 4. Second hydraulic oil pump; 5. First relief valve; 6. Second relief valve; 17. Third relief valve; 7. First directional valve; 8. Second directional valve; 9. Upward directional valve; 10. Downward directional valve; 11. First check valve; 19. Second check valve; 12. Flow feedback device; 13. Shut-off valve; 14. Rupture valve; 15. Hydraulic cylinder; 16. Manual emergency lowering valve; 18. Manual pump. Detailed Implementation

[0032] The specific embodiments of this application are described in detail below with reference to the accompanying drawings.

[0033] Example: Reference Figure 1-4 A dual-pump control system for a hydraulic elevator includes a hydraulic oil tank 1, a first hydraulic oil pump 3, a second hydraulic oil pump 4, and at least one hydraulic cylinder 15 for driving the elevator's lifting and lowering. The first hydraulic oil pump 3 and the second hydraulic oil pump 4 supply oil to the hydraulic cylinder 15. The hydraulic cylinder 15 is supplied with oil through the dual-pump system of the first hydraulic oil pump 3 and the second hydraulic oil pump 4. The first hydraulic oil pump 3 is the main pump and the commonly used pump, while the second hydraulic oil pump 4 is the auxiliary pump and the standby pump, thereby reducing the failure rate of elevator shutdowns due to hydraulic pump failure.

[0034] The hydraulic system also includes a first check valve 11, an upward directional valve 9, and a downward directional valve 10. The first check valve 11 is located in the oil supply circuit of the hydraulic cylinder 15. The upward directional valve 9 is connected in parallel to the front end of the first check valve, and the downward directional valve 10 is connected in parallel to the rear end of the first check valve. Both the upward directional valve 9 and the downward directional valve 10 are connected to the hydraulic oil tank 1. Both the upward directional valve 9 and the downward directional valve 10 are two-position, two-way valves used to control the on / off state of the oil circuit.

[0035] When the elevator is going up, valve 9 in the upward direction is off, and valve 10 in the downward direction is off.

[0036] When the elevator is going down, valve 9 is open for going up and valve 10 is open for going down.

[0037] The hydraulic cylinder 15's oil supply circuit is also equipped with a flow feedback device 12, a shut-off valve 13, and a rupture valve 14. The flow feedback device 12 is an electrical contact pressure gauge. The shut-off valve 13 acts as the main valve of the oil circuit, used to lock the entire elevator system after the elevator stops. It requires manual operation and is located in the elevator machine room, typically on the oil circuit connecting the hydraulic cylinder 15 to the check valve and the downward direction valve 10. The rupture valve 14 is a valve that automatically closes when the flow rate increases in the predetermined hydraulic oil flow direction, causing the pressure difference between the valve inlet and outlet to exceed a set value. It consists of a differential pressure reducing valve and a throttle valve and is located at the lower end of the hydraulic cylinder 15. The rupture valve 14 should be able to stop the descending car and keep it stationary. The rupture valve 14 should activate no later than when the car's descending speed reaches the rated descending speed plus 0.3 m / s.

[0038] The inlet ends of the first hydraulic pump 3 and the second hydraulic pump 4 are connected to the filter 2. The output ends of the first hydraulic pump 3 and the second hydraulic pump 4 are respectively equipped with a first directional valve 7 and a second directional valve 8 to control the flow of the oil circuit. The output ends of the first hydraulic pump 3 and the second hydraulic pump 4 are also respectively equipped with a first relief valve 5 and a second relief valve 6. Both the first directional valve 7 and the second directional valve 8 are two-position, two-way valves used to control the flow of the oil circuit. The set working pressure of the first relief valve 5 and the second relief valve 6 should not exceed 140% of the full load pressure. Considering the excessive internal losses of the hydraulic system, the pressure value of the relief valve can be adjusted higher, but it must not exceed 170% of the full load pressure.

[0039] The hydraulic system also includes a manual pump 18 and a second check valve 19. The manual pump 18 supplies oil to the hydraulic cylinder 15. The second check valve 19 is located at the output end of the manual pump 18 and is connected to the rear end of the first check valve 11. The output end of the manual pump 18 is equipped with a third relief valve 17. When the hydraulic elevator malfunctions and stops operating, the manual pump 18 must be used to lift the car upwards. The manual pump 18 is located in the machine room and should be connected to the oil line between the first check valve 11 or the downward directional valve 10 and the shut-off valve 13. The manual pump 18 is equipped with a third relief valve 17, and the set pressure of the third relief valve 17 must not exceed 2.3 times the full load pressure.

[0040] The hydraulic system also includes a manual emergency descent valve 16, which is connected in parallel with the downward directional valve 10. The manual emergency descent valve 16 is located in the machine room. In the event of a power outage, the manually operated emergency descent valve in the machine room should function reliably; it should maintain the descent of the car by continuous manual pressure.

[0041] It also includes a control motherboard, which receives the output signal of the flow feedback device 12 and is used to control the first hydraulic oil pump 3, the second hydraulic oil pump 4, the first reversing valve 7, the second reversing valve 8, the upward directional valve 9, and the downward directional valve 10.

[0042] The following describes the hydraulic oil flow and component operation under various elevator operating conditions:

[0043] When the door is opened at the level: the hydraulic oil pump is not working, the first reversing valve 7 and the second reversing valve 8 are in the closed position, the upward directional valve 9 is in the open position, and excess hydraulic oil can flow back to the hydraulic oil tank 1.

[0044] When the elevator is moving upwards: the hydraulic oil pump works, and the hydraulic oil is filtered through the filter 2 from the hydraulic oil tank 1. The first reversing valve 7 and the second reversing valve 8 are electrically controlled to open, the upward direction valve 9 is electrically controlled to close, and the downward direction valve 10 is in the closed position. The hydraulic oil flows to the hydraulic cylinder 15 through the first check valve 11, the shut-off valve 13, and the rupture valve 14, which lifts the car upwards.

[0045] When the elevator descends: the hydraulic oil in the hydraulic cylinder 15 flows to the hydraulic oil tank 1 through the rupture valve 14 and the shut-off valve 13. At this time, the downward directional valve 10 is electrically opened. On the one hand, the hydraulic oil in the hydraulic cylinder 15 flows back to the hydraulic oil tank 1 through the downward directional valve 10 due to the reverse shut-off function of the first check valve 11. On the other hand, the hydraulic pump works, the first reversing valve 7 and the second reversing valve 8 are electrically opened, and the upward directional valve 9 is in the connected position. The hydraulic oil flows back to the hydraulic oil tank 1 from the oil tank through the filter 2, the hydraulic oil pump, the first reversing valve 7 and the second reversing valve 8, and the upward directional valve 9.

[0046] Emergency Rescue Operation: The emergency rescue operation of the hydraulic elevator is achieved through the manual pump 18 and manual emergency operation. When the elevator is trapped and the car needs to be raised, the manual pump 18 pumps the hydraulic oil in the hydraulic oil tank 1 into the circuit, and flows through the second one-way valve 19, the shut-off valve 13, and the rupture valve 14 to the hydraulic cylinder 15 to achieve upward lifting. When the elevator is trapped and the car needs to be lowered, the manual emergency lowering valve 16 is manually operated. The manual emergency lowering valve 16 is manually in the open state, and the hydraulic oil in the hydraulic cylinder 15 flows back to the hydraulic oil tank 1 through the rupture valve 14, the shut-off valve 13, and the manual emergency lowering valve 16 to achieve downward movement.

[0047] The dual-pump control system for the hydraulic elevator in this embodiment uses two pumps for control, which can greatly reduce entrapment accidents caused by hydraulic pump failure. The dual-pump control electrical circuit is as follows: Figure 2 As shown.

[0048] exist Figure 2 In the text, M1 and M2 refer to the motors in the two hydraulic pumps, respectively.

[0049] The hydraulic oil pump is powered by three-phase electricity. The power supply circuit is equipped with a circuit breaker QS1 and a fuse FU1.

[0050] The power supply circuit of the first hydraulic pump is connected in series with the normally open contact of the first relay KM1 and the first thermal relay FR1; the power supply circuit of the second hydraulic pump is connected in series with the normally open contact of the second relay KM2 and the second thermal relay FR2.

[0051] It also includes a control loop, the design logic of which is as follows:

[0052] The control circuit is driven by a 220V voltage and includes a circuit breaker QF2, a fuse FU2, and an emergency stop switch.

[0053] The control loop includes a first branch, a second branch, and a third branch.

[0054] The first branch includes a series-connected rotary switch first contact, a stop button SB1, a start button SB2, a first relay KM1, and a normally closed contact of a first thermal relay FR1. The start button SB2 is connected in parallel with the normally open contact of the first relay KM1. The first branch is the main pump starting circuit. When the start button SB2 is operated, the first relay KM1 is energized, and the main pump starts working. The start button SB2 and the normally open contact of the first relay KM1 are connected in parallel, and the self-locking holding circuit operates.

[0055] The second branch includes a series connection of the first contact of a rotary switch, the normally closed contact of the first relay KM1, the normally open contact of the first thermal relay FR1, the second relay KM2, and the normally closed contact of the second thermal relay FR2. This second branch is the automatic start circuit for the auxiliary pump. When the main pump fails, the normally open contact of the first thermal relay FR1 closes, the normally closed contact of the first relay KM1 resets, the power supply to the main pump is disconnected, the second branch is activated, the second relay KM2 is energized, and the auxiliary pump starts.

[0056] The third branch includes the second contact of a rotary switch, a stop button SB4, a start button SB5, a second relay KM2, and a normally closed contact of a second thermal relay FR2. The start button SB5 is connected in parallel with the normally open contact of the second relay KM2. This third branch is the auxiliary pump starting circuit. When the auxiliary pump needs to be started, the rotary switch is rotated to the second contact, and the start button SB5 is operated. The second relay KM2 is energized, and the auxiliary pump starts. The start button SB5 and the normally open contact of the second relay KM2 are connected in parallel, maintaining the operation of the self-locking circuit.

[0057] The power supply neutral (N) line is connected to the common terminal of the rotary selector switch. The rotary selector switch can be either a three-position switch or a two-position switch.

[0058] The control circuit also includes an intermediate relay KA2 connected in series and its normally open contact. A pressure changeover switch is connected in parallel across the two ends of the normally open contact of the intermediate relay KA2. The common terminal of the pressure changeover switch is connected to the first contact of the rotary switch, thus connecting it in parallel with the first and second branches. The pressure changeover switch has two contacts: a high-pressure contact and a low-pressure contact. The low-pressure contact is connected to the intermediate relay KA2. The high-pressure contact is connected to the intermediate relay KA1, and the normally closed contact of the intermediate relay KA1 is connected in series with the normally open contact of the intermediate relay KA2.

[0059] The normally open contact of the intermediate relay KA2 is connected in parallel across the normally closed contact of the first relay KM1 and the normally open contact of the first thermal relay FR1. The pressure switching switch is controlled by the main control board or by an electrical contact pressure gauge installed in the hydraulic cylinder oil supply circuit. When the electrical contact pressure gauge detects low pressure, it switches to the low pressure point. This circuit is used to start the auxiliary pump when the hydraulic system pressure is insufficient. When the hydraulic system is working normally, and when the hydraulic system pressure decreases, the electrical contact pressure gauge activates, the intermediate relay KA2 is energized, and then the second relay KM2 is energized, starting the auxiliary pump. The dual pumps work to increase the hydraulic system pressure.

[0060] In summary, the dual-pump control system in this embodiment has the following four operating modes:

[0061] (1) Main pump working mode. Manually start SB2, the first relay KM1 is energized, and the main pump M1 starts working.

[0062] (2) Auxiliary pump working mode. When the main pump fails, the first thermal relay FR1 overheats, the normally open contact of the first thermal relay FR1 closes, the second relay KM2 is energized, and the auxiliary pump starts to work.

[0063] (3) Main and auxiliary pump working mode. When the electric pressure gauge (flow feedback device 12) detects that the pressure in the hydraulic circuit decreases, it will automatically switch from high pressure to low pressure. At this time, the main and auxiliary pumps work at the same time to meet the overall pressure of the hydraulic system.

[0064] (4) Manual Maintenance Mode. This mode is set up when the main pump needs maintenance while the elevator is running. By manually operating the rotary switch from the normal to the standby position, i.e., switching from the first contact to the second contact, you can switch from the main pump to the auxiliary pump without affecting the normal operation of the elevator. When the normal position is rotated to the standby position, the main pump running circuit is disconnected and the main pump stops running. At this time, you need to press the start button SB5 to start the auxiliary pump.

[0065] The above description is only a preferred embodiment of this application. It should be noted that for those skilled in the art, several modifications and improvements can be made without departing from the inventive concept of this application, and these all fall within the protection scope of this application.

Claims

1. A dual-pump control system for a hydraulic elevator, characterized in that, It includes a hydraulic oil tank (1), a first hydraulic oil pump (3), a second hydraulic oil pump (4), and at least one hydraulic cylinder (15) for driving the elevator to move up and down. The first hydraulic oil pump (3) and the second hydraulic oil pump (4) are used to supply oil to the hydraulic cylinder (15). It also includes a first check valve (11), an upward directional valve (9), and a downward directional valve (10). The first check valve (11) is installed in the oil supply circuit of the hydraulic cylinder (15). The upward directional valve (9) is connected in parallel to the front end of the first check valve. The downward directional valve (10) is connected in parallel to the rear end of the first check valve. Both the upward directional valve (9) and the downward directional valve (10) are connected to the hydraulic oil tank (1). The power supply circuit of the first hydraulic oil pump (3) is connected in series with the normally open contact of the first relay KM1 and the first thermal relay FR1; The power supply circuit of the second hydraulic oil pump (4) is connected in series with the normally open contact of the second relay KM2 and the second thermal relay FR2; It also includes a control loop, which comprises a first branch, a second branch, and a third branch; The first branch includes a normally closed contact of a rotary switch, a stop button SB1, a start button SB2, a first relay KM1, and a first thermal relay FR1 connected in series. The start button SB2 is connected in parallel with the normally open contact of the first relay KM1. The second branch includes the first contact of a rotary switch connected in series, the normally closed contact of the first relay KM1, the normally open contact of the first thermal relay FR1, the second relay KM2, and the normally closed contact of the second thermal relay FR2. The third branch includes the second contact of the rotary switch, the stop button SB4, the start button SB5, the second relay KM2, and the normally closed contact of the second thermal relay FR2. The start button SB5 and the normally open contact of the second relay KM2 are connected in parallel.

2. The hydraulic elevator dual-pump control system according to claim 1, characterized in that, The hydraulic cylinder (15) is also equipped with a flow feedback device (12), a shut-off valve (13), and a rupture valve (14) in its oil supply circuit.

3. The hydraulic elevator dual-pump control system according to claim 2, characterized in that, The output ends of the first hydraulic oil pump (3) and the second hydraulic oil pump (4) are respectively provided with a first reversing valve (7) and a second reversing valve (8) to control whether the oil circuit is open or closed. The output ends of the first hydraulic oil pump (3) and the second hydraulic oil pump (4) are also respectively provided with a first relief valve (5) and a second relief valve (6).

4. The hydraulic elevator dual-pump control system according to claim 1, characterized in that, It also includes a manual pump (18) and a second check valve (19), the manual pump (18) being used to supply oil to the hydraulic cylinder (15), and the second check valve (19) being located at the output end of the manual pump (18), the output end of the second check valve (19) being connected to the rear end of the first check valve (11); The output end of the manual pump (18) is equipped with a third overflow valve (17).

5. The hydraulic elevator dual-pump control system according to claim 1, characterized in that, It also includes a manual emergency descent valve (16), which is connected in parallel with the down directional valve (10).

6. The hydraulic elevator dual-pump control system according to claim 3, characterized in that, It also includes a control motherboard, which receives the output signal of the flow feedback device (12) and is used to control the first hydraulic oil pump (3), the second hydraulic oil pump (4), the first directional valve (7), the second directional valve (8), the upward directional valve (9), and the downward directional valve (10).

7. The hydraulic elevator dual-pump control system according to claim 6, characterized in that, The control circuit also includes an intermediate relay KA2 connected in series and its normally open contact. A pressure switching switch is connected in parallel across the two ends of the normally open contact of the intermediate relay KA2. The normally open contact of the intermediate relay KA2 is connected in parallel across the two ends of the normally closed contact of the first relay KM1 and the normally open contact of the first thermal relay FR1. The pressure switching switch is controlled by the main control board or by the electrical contact pressure gauge installed in the oil supply circuit of the hydraulic cylinder (15).

8. The hydraulic elevator dual-pump control system according to claim 1, characterized in that, The control circuit is also equipped with a circuit breaker QF2, a fuse FU2, and an emergency stop switch.

9. The hydraulic elevator dual-pump control system according to claim 1, characterized in that, The power supply circuits of the first hydraulic oil pump (3) and the second hydraulic oil pump (4) are equipped with a circuit breaker QS1 and a fuse FU1.

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